The present invention relates to microparticle analysis devices and microparticle analysis methods. More specifically, the invention relates to a microparticle analysis device and so forth to optically analyze characteristics of microparticles such as cells and microbeads.
As a related art, microparticle analysis devices are used in which microparticles flowing in a flow cell or a flow path formed on a microchip are irradiated with light and scattered light from the microparticles and fluorescence generated from the microparticles themselves or a fluorescent substance given to the microparticles as a labeling substance are detected to measure optical characteristics of the microparticles. In the microparticle analysis devices, fractional collection of a population (group) determined to be one satisfying a predetermined condition among the microparticles as a result of the measurement of the optical characteristics is also performed. Among the microparticle analysis devices, particularly a device to measure optical characteristics of cells as the microparticles and perform fractional collection of a cell population satisfying a predetermined condition is called e.g. a flow cytometer or a cell sorter.
For example, Japanese Patent Laid-open No. 2007-46947 (hereinafter, Patent Document 1) discloses “a flow cytometer comprising a plurality of light sources to radiate a plurality of excitation light beams having wavelengths different from each other with a predetermined cycle and phases different from each other, and an optical guide member to guide the plurality of excitation light beams onto the same incident light path and condense the light beams on dyed particles.” This flow cytometer includes the plurality of light sources to radiate a plurality of excitation light beams having wavelengths different from each other, the optical guide member to guide the plurality of excitation light beams onto the same incident light path and condense the light beams on dyed particles, and a plurality of fluorescence detectors to detect fluorescence generated due to excitation of the particles by each of the plurality of excitation light beams and output a fluorescence signal (see claims 1 and 3 and FIGS. 1 and 3 in Patent Document 1).
In the related-art microparticle analysis device like that disclosed in Patent Document 1, fluorescence generated from microparticles or a fluorescent substance given to the microparticles as a labeling substance is spatially divided into fluorescence in plural wavelength regions by using a wavelength filter and a dichroic mirror, and the divided fluorescence in the respective wavelength regions is detected by individual detectors.
FIG. 6 schematically shows the optical path for the fluorescence detection in the related-art microparticle analysis device. Light (excitation light) from a light source indicated by reference numeral 11 in the diagram passes through a collimator lens 12 and a mirror 13 to be irradiated on microparticles P flowing in a flow cell or a flow path formed on a microchip by a condenser lens 14. In the diagram, arrowhead F indicates the flow sending direction of the sheath flow in the flow cell or the like.
The fluorescence generated from the microparticles P or a fluorescent substance given to the microparticles P as a labeling substance due to the irradiation with the excitation light passes through a condenser lens 15 and is transmitted through plural wavelength filters 161 to 164 sequentially. At this time, fluorescence in a predetermined wavelength region is dispersed by each wavelength filter. The fluorescence dispersed by the respective wavelength filters is detected by detectors 171 to 174 provided for each of the wavelength filters and converted to an electrical signal. FIG. 7 shows one example of the wavelength regions of the fluorescence detected by the detectors 171 to 174. This example corresponds to the case in which fluorescence in a wavelength region λ1 is detected by the detector 171 and fluorescence in wavelength regions λ2 to λ4 is detected by the detectors 172 to 174, respectively.